ABSTRACT The primary aim of this new University of Colorado transdisciplinary training program is to prepare outstanding pre-(PhD) and post-(PhD, MD/PhD, MD) doctoral fellows for science careers that address cutting-edge basic and clinical research questions that represent the future of biomedical research. The training program will foster transdisciplinary research with state-of-the-art technologies and methods used by participating faculty laboratories, and will evaluate and enhance the mentoring skills of early career faculty. The program is novel in that it exposes trainees and faculty from diverse biomedical research backgrounds to collaborative sleep and circadian science. Similarly, current sleep and circadian trainees and expert faculty benefit from meaningful interactions with investigators from different research backgrounds, particularly those from biomedical research areas that are of high importance to the NIH/NHLBI. The research training activities of the 22 participating faculty emphasize transdisciplinary training in sleep and circadian physiology with research programs focused on cardiovascular, genetics/genomics, metabolomics, proteomics, biomarker development, bioinformatics, biostatistics, epidemiology, stress physiology, immunology, endocrinology, metabolism, obesity, diabetes, neuroscience, pediatrics, development, aging, psychiatry, and pulmonary and behavioral sleep medicine. Because our goal is to provide transdisciplinary and translational research career training, major program components of this T32 include the Department of Integrative Physiology, the Department of Psychology and Neuroscience, and the Institute for Behavioral Genetics at University of Colorado Boulder, and multiple clinical departments and divisions at University of Colorado School of Medicine Anschutz Medical Campus. The existing fruitful and collaborative environment is a strength of this training grant. Of the existing T32s at the University of Colorado, this would be the only one dedicated to transdisciplinary sleep and circadian science. Also, it would become the first sleep and circadian T32 in the Western United States. The specific aims of the training program are to recruit, select and retain outstanding trainees; promote inclusive excellence; provide high quality training, educational, and career development experiences to prepare trainees for research-intensive and research-related careers; shape tomorrow?s scientific leaders; foster rigorous and collaborative sleep and circadian science; ensure successful progress of trainees toward predetermined milestones defined in Individual Development Plans; enhance the mentoring skills of faculty through a formal mentoring training plan; ensure conscientious program evaluation; and expand the number of investigators conducting transdisciplinary sleep and circadian science. We request support for one pre-doctoral and one post-doctoral trainee in year 1, and two pre-doctoral and two post-doctoral trainees in years 2-5.